Improvement of the battery capacity of portable units has long been a priority area of development. For example, the battery capacity of mobile telephones has steadily increased since the first units appeared on the market and it is currently common to have standby times of several hundred hours.
However, the connection time is often significantly less, simply because the various energy-saving methods and solutions that have hitherto been implemented primarily affect the standby time. Satisfactory methods are still lacking for minimizing the energy requirement when connected, that is, during periods in which the unit is transmitting. There is still generally a continually increasing requirement for longer stand by time.